Screening and Surveillance for Barrett's Esophagus
Screening and Surveillance for Barrett's Esophagus
Although there have been a number of studies evaluating the cost-effectiveness of surveillance for Barrett's esophagus, the majority of studies used the EAC incidence rate of 0.5% that is now suspected to be an overestimate. Along with the progression rate from Barrett's esophagus to EAC, the diagnostic accuracy of endoscopy needs to be updated when re-evaluating the cost-effectiveness of the current surveillance program. A systematic-review by Hirst et al. concluded that the current endoscopic surveillance strategy for nondysplasic Barrett's esophagus patients is unlikely to be cost-effective, unless new technologies improve the quality-adjusted survival benefit from the surveillance. Because the majority of the cost-effectiveness analyses used the rates of misdiagnosis from a personal communication with one pathologist in 1994, the rates used in prior studies may not be representative of the current endoscopic technology which has improved since then (see following paragraphs). These technological advances may improve the predictive value of endoscopic surveillance and consequently, the cost-effectiveness of the Barrett's esophagus surveillance program.
Surveillance utilizing white light endoscopy (WLE) has been critical in recognition of lesions, but when viewed by WLE, dysplastic lesions are still difficult to distinguish from nondysplastic mucosa. Because only a small fraction of the Barrett's esophagus mucosa is randomly biopsied, it is difficult to obtain an accurate assessment regarding the presence of cancer or dysplasia due to sampling error and poor sensitivity. Advanced endoscopic imaging technologies, such as narrow band imaging (NBI), autofluorescence imaging (AFI), and confocal laser endomicroscopy (CLE), may improve the accuracy in the detection of dysplasia and early cancer, increasing the effectiveness of endoscopic surveillance.
NBI allows for better detection of early neoplastic lesions by visualizing the patterns produced by subsurface vascular changes. It has been demonstrated that NBI can detect significantly more patients with dysplasia and higher grades of dysplasia with fewer biopsy samples compared with standard resolution WLE. A meta-analysis on the performance and clinical utility of NBI in upper endoscopy found a sensitivity of 97% (95% CI, 0.89–0.99), a specificity of 94% (95% CI, 0.60–0.99), and an overall accuracy of 96% (95% CI, 0.72–0.99) of NBI in differentiating dysplasia from nondysplastic Barrett's esophagus.
Recent studies have evaluated the efficiency of using NBI in conjunction with other advanced imaging technologies. Curvers et al. performed a multicenter randomized study that evaluated endoscopic trimodal imaging (ETMI), NBI used in combination with high-resolution endoscopy and AFI, and found that it improved the detection of HGD and early cancer in Barrett's esophagus. ETMI significantly improved the targeted detection of HGD and EAC compared with standard video endoscopy. In another multicenter randomized controlled trial, Sharma et al. examined the diagnostic characteristics of probe-based CLE (pCLE), high-definition white-light endoscopy (HD-WLE), NBI, HD-WLE/NBI, or HD-WLE/pCLE in detecting HGD and early cancer. They found that pCLE combined with HD-WLE significantly improved the ability to detect HGD and early cancer in Barrett's esophagus patients compared with HD-WLE alone. The sensitivity and specificity for HD-WLE were 34.2% and 92.7%, respectively, compared with 68.3% and 87.8%, respectively, for HD-WLE or pCLE (P = 0.002 and P < 0.001, respectively).
The aforementioned studies that have evaluated advances in imaging techniques provide promising results, which may be applied to Barrett's esophagus endoscopic surveillance. With the ability to improve the detection of HGD and early cancer, these enhanced diagnostic techniques have the potential to make the current Barrett's esophagus/EAC surveillance strategies more cost-effective. Additionally, the ability to more reliably detect HGD during Barrett's esophagus surveillance may provide opportunities for patients to choose nonsurgical therapeutic options, such as radiofrequency ablation, which would also affect the cost-effectiveness of a Barrett's esophagus surveillance regimen. The enhanced diagnostic accuracy obtained from advanced imaging techniques needs to be considered when re-evaluating the current surveillance Barrett's esophagus/EAC surveillance strategies, particularly as they become standard of care.
Improvements in Endoscopic Imaging Techniques
Although there have been a number of studies evaluating the cost-effectiveness of surveillance for Barrett's esophagus, the majority of studies used the EAC incidence rate of 0.5% that is now suspected to be an overestimate. Along with the progression rate from Barrett's esophagus to EAC, the diagnostic accuracy of endoscopy needs to be updated when re-evaluating the cost-effectiveness of the current surveillance program. A systematic-review by Hirst et al. concluded that the current endoscopic surveillance strategy for nondysplasic Barrett's esophagus patients is unlikely to be cost-effective, unless new technologies improve the quality-adjusted survival benefit from the surveillance. Because the majority of the cost-effectiveness analyses used the rates of misdiagnosis from a personal communication with one pathologist in 1994, the rates used in prior studies may not be representative of the current endoscopic technology which has improved since then (see following paragraphs). These technological advances may improve the predictive value of endoscopic surveillance and consequently, the cost-effectiveness of the Barrett's esophagus surveillance program.
Surveillance utilizing white light endoscopy (WLE) has been critical in recognition of lesions, but when viewed by WLE, dysplastic lesions are still difficult to distinguish from nondysplastic mucosa. Because only a small fraction of the Barrett's esophagus mucosa is randomly biopsied, it is difficult to obtain an accurate assessment regarding the presence of cancer or dysplasia due to sampling error and poor sensitivity. Advanced endoscopic imaging technologies, such as narrow band imaging (NBI), autofluorescence imaging (AFI), and confocal laser endomicroscopy (CLE), may improve the accuracy in the detection of dysplasia and early cancer, increasing the effectiveness of endoscopic surveillance.
NBI allows for better detection of early neoplastic lesions by visualizing the patterns produced by subsurface vascular changes. It has been demonstrated that NBI can detect significantly more patients with dysplasia and higher grades of dysplasia with fewer biopsy samples compared with standard resolution WLE. A meta-analysis on the performance and clinical utility of NBI in upper endoscopy found a sensitivity of 97% (95% CI, 0.89–0.99), a specificity of 94% (95% CI, 0.60–0.99), and an overall accuracy of 96% (95% CI, 0.72–0.99) of NBI in differentiating dysplasia from nondysplastic Barrett's esophagus.
Recent studies have evaluated the efficiency of using NBI in conjunction with other advanced imaging technologies. Curvers et al. performed a multicenter randomized study that evaluated endoscopic trimodal imaging (ETMI), NBI used in combination with high-resolution endoscopy and AFI, and found that it improved the detection of HGD and early cancer in Barrett's esophagus. ETMI significantly improved the targeted detection of HGD and EAC compared with standard video endoscopy. In another multicenter randomized controlled trial, Sharma et al. examined the diagnostic characteristics of probe-based CLE (pCLE), high-definition white-light endoscopy (HD-WLE), NBI, HD-WLE/NBI, or HD-WLE/pCLE in detecting HGD and early cancer. They found that pCLE combined with HD-WLE significantly improved the ability to detect HGD and early cancer in Barrett's esophagus patients compared with HD-WLE alone. The sensitivity and specificity for HD-WLE were 34.2% and 92.7%, respectively, compared with 68.3% and 87.8%, respectively, for HD-WLE or pCLE (P = 0.002 and P < 0.001, respectively).
The aforementioned studies that have evaluated advances in imaging techniques provide promising results, which may be applied to Barrett's esophagus endoscopic surveillance. With the ability to improve the detection of HGD and early cancer, these enhanced diagnostic techniques have the potential to make the current Barrett's esophagus/EAC surveillance strategies more cost-effective. Additionally, the ability to more reliably detect HGD during Barrett's esophagus surveillance may provide opportunities for patients to choose nonsurgical therapeutic options, such as radiofrequency ablation, which would also affect the cost-effectiveness of a Barrett's esophagus surveillance regimen. The enhanced diagnostic accuracy obtained from advanced imaging techniques needs to be considered when re-evaluating the current surveillance Barrett's esophagus/EAC surveillance strategies, particularly as they become standard of care.
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